Abstract: Linear voltage regulators and a method for low-dropout LDO regulators are presented. Specifically, LDO regulators with circuits for noise reduction are discussed. A linear voltage regulator has a first noise reduction filter, an error amplifier circuit, and a pass device. The pass device may be coupled between an input and output terminal of the regulator. The error amplifier circuit generates a control signal for controlling the pass device based on a filtered reference signal and an output voltage at the output terminal of the regulator. The first noise reduction filter generates the filtered reference signal based on a reference voltage of a reference voltage source by reducing noise originating from the reference voltage source or noise generated by one or more passive components coupled between the reference voltage source and the first noise reduction filter.

Abstract: A method and circuit for trimming a bandgap reference are described. The bandgap reference circuit comprises a first diode which is arranged in series with a first resistor between a reference point and a reference potential VSS. The circuit also comprises a second diode which is arranged in series with a second resistor and a third resistor between the reference point and the reference potential VSS. In addition, the bandgap reference circuit comprises a trimming network, wherein a bandgap reference voltage VBG CORE is provided at a midpoint between the trimming network and the current source. The circuit also comprises an operational amplifier. The method (700) comprises measuring a first diode voltage across a replica element of the first diode; determining a first resistance of a replica element of the first resistor; and setting a resistance of the trimming network using the first diode voltage and the first resistance.

Abstract: A method and circuit for trimming a bandgap reference are described. The bandgap reference circuit comprises a first diode which is arranged in series with a first resistor between a reference point and a reference potential VSS. The circuit also comprises a second diode which is arranged in series with a second resistor and a third resistor between the reference point and the reference potential VSS. In addition, the bandgap reference circuit comprises a trimming network, wherein a bandgap reference voltage VBG CORE is provided at a midpoint between the trimming network and the current source. The circuit also comprises an operational amplifier. The method (700) comprises measuring a first diode voltage across a replica element of the first diode; determining a first resistance of a replica element of the first resistor; and setting a resistance of the trimming network using the first diode voltage and the first resistance.

Abstract: Systems and methods for providing a rapid switchable high voltage power transistor driver with a constant gate-source control voltage have been disclosed. A low voltage control stage keeps the gate-source voltage constant in spite of temperature and process variations. A high voltage supply voltage can vary between about 5.5 Volts and about 40 Volts. The circuit allows a high switching frequency of e.g. 1 MHz and minimizes static power dissipation.

Abstract: Systems and methods to achieve a circuit for driving one or more infrared transmitter LEDs with temperature compensation have been disclosed. In a preferred embodiment of the invention the circuit has been applied for a rain sensing system. The junction temperature of the LED is measured and compensated by adjusting the driver current of a voltage-to-current converter driving the LED. The LED junction temperature is measured by comparing the difference in the forward diode voltage at different current densities. This voltage difference is extracted when switching the drive currents between different constant values. The measurement results are converted to digital values, which are used by a buffered dual ladder resistive DAC structure to adjust the drive current to temperature variations.

Abstract: Systems and methods for providing a rapid switchable high voltage power transistor driver with a constant gate-source control voltage have been disclosed. A low voltage control stage keeps the gate-source voltage constant in spite of temperature and process variations. A high voltage supply voltage can vary between about 5.5 Volts and about 40 Volts. The circuit allows a high switching frequency of e.g. 1 MHz and minimizes static power dissipation.

Abstract: Systems and methods for a front-end circuit receiving a current from a photodiode receiving a signal light and ambient light have been disclosed. In a preferred embodiment the front-end circuit accommodates a photo diode current, generated by a signal light from an infrared LED diode in presence of a current generated by ambient light for a rain-sensing system. The circuit invented has a high dynamic range comprising a programmable transresistance amplifier, a switched capacitor programmable gain amplifier and a switched capacitor fourth-order oversampled sigma-delta A/D converter including an optimized digital filter. Furthermore coarse and fine IDACs are used to successively subtract a current generated by ambient light.

Abstract: Systems and methods for a front-end circuit receiving a current from a photodiode receiving a signal light and ambient light have been disclosed. In a preferred embodiment the front-end circuit accommodates a photo diode current, generated by a signal light from an infrared LED diode in presence of a current generated by ambient light for a rain-sensing system. The circuit invented has a high dynamic range comprising a programmable transresistance amplifier, a switched capacitor programmable gain amplifier and a switched capacitor fourth-order oversampled sigma-delta ND converter including an optimized digital filter. Furthermore coarse and fine IDACs are used to successively subtract a current generated by ambient light.

Abstract: Systems and methods to achieve a circuit for driving one or more infrared transmitter LEDs with temperature compensation have been disclosed. In a preferred embodiment of the invention the circuit has been applied for a rain sensing system. The junction temperature of the LED is measured and compensated by adjusting the driver current of a voltage-to-current converter driving the LED. The LED junction temperature is measured by comparing the difference in the forward diode voltage at different current densities. This voltage difference is extracted when switching the drive currents between different constant values. The measurement results are converted to digital values, which are used by a buffered dual ladder resistive DAC structure to adjust the drive current to temperature variations.

Abstract: An integrated circuit for a charge pump with a charge stage and a pump stage and a single High-Voltage PMOS (HVPMOS) transistor as the main switch for each stage and two times two minimum HVPMOS transistors in series as a bulk switch with fixed bulk connections, where the minimum HVPMOS transistors are smaller sized transistors than the transistors of the main switch. The bulk of the main switch is switched synchronously to the voltage node of the HVPMOS transistor of the main switch to force the bulk voltage (VB) to be equal or larger than either the source voltage (VS) or the drain voltage (VD). Two non-overlapping clock signals are used to trigger the HVPMOS transistors of the charge and pump stage.

Abstract: An integrated circuit for a charge pump with a charge stage and a pump stage and a single High-Voltage PMOS (HVPMOS) transistor as the main switch for each stage and two times two minimum HVPMOS transistors in series as a bulk switch with fixed bulk connections, where the minimum HVPMOS transistors are smaller sized transistors than the transistors of the main switch. The bulk of the main switch is switched synchronously to the voltage node of the HVPMOS transistor of the main switch to force the bulk voltage (VB) to be equal or larger than either the source voltage (VS) or the drain voltage (VD). Two non-overlapping clock signals are used to trigger the HVPMOS transistors of the charge and pump stage.

Abstract: Circuits and methods to achieve a regulated analog switch being capable to provide an output-voltage not exceeding a defined limit are disclosed. In a preferred embodiment a car battery provides a supply voltage up to 40 Volts, wherein a load must not have an output voltage higher than 22 Volts. The drain-source ON-resistance of the switch, realized by a high-voltage MOSFET, is kept to a minimum. The voltage regulation of the preferred embodiment is performed by a single stage operational amplifier and a two-stage amplifier having Miller compensation.

Abstract: Circuits and methods to achieve a regulated analog switch being capable to provide an output-voltage not exceeding a defined limit are disclosed. In a preferred embodiment a car battery provides a supply voltage up to 40 Volts, wherein a load must not have an output voltage higher than 22 Volts. The drain-source ON-resistance of the switch, realized by a high-voltage MOSFET, is kept to a minimum. The voltage regulation of the preferred embodiment is performed by a single stage operational amplifier and a two-stage amplifier having Miller compensation.

Abstract: The supply voltage of an on-chip flash memory is regulated with two feedback loops. One loop comprises the flash memory, a register, and a voltage regulator with bandgap reference to regulate the supply voltage. The other loop comprises the flash memory, another register, an amplifier with bandgap reference, and comparators to monitor the supply voltage and adjust the threshold of the signals which control the operation of the flash memory and registers. The calibration data controls variable resistive means in the feedback paths of the voltage regulator and in the calibration of the threshold values of the control signals. Calibration data is held in the registers when the supply voltage is out-of-range to prevent self-start up.

Abstract: The supply voltage of an on-chip flash memory is regulated with two feedback loops. One loop comprises the flash memory, a register, and a voltage regulator with bandgap reference to regulate the supply voltage. The other loop comprises the flash memory, another register, an amplifier with bandgap reference, and comparators to monitor the supply voltage and adjust the threshold of the signals which control the operation of the flash memory and registers. The calibration data controls variable resistive means in the feedback paths of the voltage regulator and in the calibration of the threshold values of the control signals. Calibration data is held in the registers when the supply voltage is out-of-range to prevent self-start up.

Abstract: Methods and circuits for chain ring oscillators having a constant duty cycle and being insensitive to ground noise have been disclosed. The ring oscillator generates n outputs with 360°/n phase shift and each stage is delayed by T 2 × n . The output of a suitable stage is selected so that a digital XOR-gate, using the output of a selected stage and the output of the nth stage, eliminates variations of the duty cycle caused by temperature and process variations. In case a 50% duty cycle is desired the stage number N of the selected stage can be calculated using the equation N=(n?1)/2. The duty cycle can be varied by selecting the output of another gate. A D-flipflop, clocked by the output of the XOR-gate removes noise from the clock pulses.